add native Enzyme rules and enhanced autodiff support

.github/dependabot.yml

@@ -0,0 +1,22 @@
+# https://docs.github.com/github/administering-a-repository/configuration-options-for-dependency-updates
+version: 2
+enable-beta-ecosystems: true # Julia ecosystem
+updates:
+  - package-ecosystem: "github-actions"
+    directory: "/" # Location of package manifests
+    schedule:
+      interval: "weekly"
+    ignore:
+      - dependency-name: "crate-ci/typos"
+        update-types: ["version-update:semver-patch", "version-update:semver-minor"]
+  - package-ecosystem: "julia"
+    directories:
+      - "/"
+      - "/docs"
+      - "/test"
+    schedule:
+      interval: "daily"
+    groups:
+      all-julia-packages:
+        patterns:
+          - "*"

.github/workflows/downgrade.yml

@@ -32,7 +32,7 @@ jobs:
             - uses: julia-actions/cache@v2
             - uses: julia-actions/julia-downgrade-compat@v1
               with:
-                  skip: LinearAlgebra, Random, Statistics
+                  skip: LinearAlgebra, Random, Statistics, Enzyme, EnzymeCore, Mooncake, ChainRulesCore, FiniteDifferences
                   projects: ., test, docs
             - uses: julia-actions/julia-buildpkg@v1
               env:

CLAUDE.md

@@ -103,6 +103,7 @@ The package requires `Vector{AbstractVector}` input format (not matrices). Each
 - The package requires Julia 1.10+ (see Project.toml compatibility)
 - Uses KernelAbstractions.jl for GPU/CPU parallelization
 - Data must be in `Vector{AbstractVector}` format (not matrices) - each point needs inferrable dimension (e.g., `SVector{2,Float64}`)
+- **Autodiff examples**: Always use DifferentiationInterface.jl for AD examples in docs and tests. This provides a unified interface over Enzyme.jl and Mooncake.jl backends.
 
 ---
 

Project.toml

@@ -19,17 +19,22 @@ StaticArraysCore = "1e83bf80-4336-4d27-bf5d-d5a4f845583c"
 SymRCM = "286e6d88-80af-4590-acc9-0001b223b9bd"
 
 [weakdeps]
+Enzyme = "7da242da-08ed-463a-9acd-ee780be4f1d9"
+EnzymeCore = "f151be2c-9106-41f4-ab19-57ee4f262869"
 Mooncake = "da2b9cff-9c12-43a0-ae48-6db2b0edb7d6"
 
 [extensions]
 RadialBasisFunctionsChainRulesCoreExt = "ChainRulesCore"
+RadialBasisFunctionsEnzymeExt = ["Enzyme", "EnzymeCore"]
 RadialBasisFunctionsMooncakeExt = ["ChainRulesCore", "Mooncake"]
 
 [compat]
 ChainRulesCore = "1.20"
 ChunkSplitters = "3"
 Combinatorics = "1"
 Distances = "0.9, 0.10"
+Enzyme = "0.13"
+EnzymeCore = "0.8"
 FiniteDifferences = "0.12.33"
 KernelAbstractions = "0.9.34"
 LinearAlgebra = "1"

benchmark/Project.toml

@@ -7,5 +7,5 @@ StaticArraysCore = "1e83bf80-4336-4d27-bf5d-d5a4f845583c"
 
 [compat]
 BenchmarkTools = "1.5"
-RadialBasisFunctions = "0.2.5"
+RadialBasisFunctions = "0.3"
 julia = "1.9"

docs/Project.toml

@@ -1,9 +1,16 @@
 [deps]
 CairoMakie = "13f3f980-e62b-5c42-98c6-ff1f3baf88f0"
 DelimitedFiles = "8bb1440f-4735-579b-a4ab-409b98df4dab"
+DifferentiationInterface = "a0c0ee7d-e4b9-4e03-894e-1c5f64a51d63"
 Documenter = "e30172f5-a6a5-5a46-863b-614d45cd2de4"
 DocumenterVitepress = "4710194d-e776-4893-9690-8d956a29c365"
+Enzyme = "7da242da-08ed-463a-9acd-ee780be4f1d9"
 LiveServer = "16fef848-5104-11e9-1b77-fb7a48bbb589"
+Mooncake = "da2b9cff-9c12-43a0-ae48-6db2b0edb7d6"
 RadialBasisFunctions = "79ee0514-adf7-4479-8807-6f72ea8967e8"
 Random = "9a3f8284-a2c9-5f02-9a11-845980a1fd5c"
 StaticArrays = "90137ffa-7385-5640-81b9-e52037218182"
+
+[compat]
+Documenter = "1"
+DocumenterVitepress = "0.3"

docs/make.jl

@@ -21,6 +21,7 @@ makedocs(;
     pages = [
         "Home" => "index.md",
         "Getting Started" => "getting_started.md",
+        "Automatic Differentiation" => "autodiff.md",
         "Quick Reference" => "quickref.md",
         "Theory" => "theory.md",
         "Internals" => "internals.md",

docs/src/.vitepress/config.mts

@@ -1,9 +1,11 @@
 import { defineConfig } from 'vitepress'
 import { tabsMarkdownPlugin } from 'vitepress-plugin-tabs'
-import mathjax3 from "markdown-it-mathjax3";
+import { mathjaxPlugin } from './mathjax-plugin'
 import footnote from "markdown-it-footnote";
 import path from 'path'
 
+const mathjax = mathjaxPlugin()
+
 function getBaseRepository(base: string): string {
   if (!base || base === '/') return '/';
   const parts = base.split('/').filter(Boolean);
@@ -18,6 +20,8 @@ const navTemp = {
   nav: [
     { text: 'Home', link: '/index' },
     { text: 'Getting Started', link: '/getting_started' },
+    { text: 'Autodiff', link: '/autodiff' },
+    { text: 'Quick Reference', link: '/quickref' },
     { text: 'Theory', link: '/theory' },
     { text: 'Internals', link: '/internals' },
     { text: 'API', link: '/api' }
@@ -45,6 +49,9 @@ export default defineConfig({
     ],
 
     vite: {
+      plugins: [
+        mathjax.vitePlugin,
+      ],
       define: {
         __DEPLOY_ABSPATH__: JSON.stringify('/'),
       },
@@ -68,11 +75,10 @@ export default defineConfig({
       },
     },
     markdown: {
-      math: true,
       config(md) {
-        md.use(tabsMarkdownPlugin),
-        md.use(mathjax3),
-        md.use(footnote)
+        md.use(tabsMarkdownPlugin);
+        md.use(footnote);
+        mathjax.markdownConfig(md);
       },
       theme: {
         light: "github-light",
@@ -92,6 +98,8 @@ export default defineConfig({
       sidebar: [
         { text: 'Home', link: '/index' },
         { text: 'Getting Started', link: '/getting_started' },
+        { text: 'Autodiff', link: '/autodiff' },
+        { text: 'Quick Reference', link: '/quickref' },
         { text: 'Theory', link: '/theory' },
         { text: 'Internals', link: '/internals' },
         { text: 'API', link: '/api' }

docs/src/.vitepress/mathjax-plugin.ts

@@ -0,0 +1,161 @@
+// adapter from https://github.com/orgs/vuepress-theme-hope/discussions/5178#discussioncomment-15642629
+// mathjax-plugin.ts
+// @ts-ignore
+import MathJax from '@mathjax/src'
+import type { Plugin as VitePlugin } from 'vite'
+import type MarkdownIt from 'markdown-it'
+import { tex as mdTex } from '@mdit/plugin-tex'
+
+const mathjaxStyleModuleID = 'virtual:mathjax-styles.css'
+
+interface MathJaxOptions {
+  font?: string
+}
+
+async function initializeMathJax(options: MathJaxOptions = {}) {
+  const font = options.font || 'mathjax-newcm'
+
+  const config: any = {
+    loader: {
+      load: [
+        'input/tex',
+        'output/svg',
+        '[tex]/boldsymbol',
+        '[tex]/braket',
+        '[tex]/mathtools',
+      ],
+    },
+    tex: {
+      tags: 'ams',
+      packages: {
+        '[+]': ['boldsymbol', 'braket', 'mathtools'],
+      },
+    },
+    output: {
+      font,
+      displayOverflow: 'linebreak',
+      mtextInheritFont: true,
+    },
+    svg: {
+      fontCache: 'none', // critical: avoids async font loading
+    },
+  }
+
+  await MathJax.init(config)
+
+  const fontData = MathJax.config.svg?.fontData
+
+  if (fontData?.dynamicFiles) {
+    const dynamicFiles = fontData.dynamicFiles
+    const dynamicPrefix: string =
+      fontData.OPTIONS?.dynamicPrefix || fontData.options?.dynamicPrefix
+
+    if (dynamicPrefix) {
+      await Promise.all(
+        Object.keys(dynamicFiles).map(async (name) => {
+          try {
+            await import(/* @vite-ignore */ `${dynamicPrefix}/${name}.js`)
+            dynamicFiles[name]?.setup?.(MathJax.startup.output.font)
+          } catch {
+            // Silently ignore missing dynamic files
+          }
+        }),
+      )
+    }
+  }
+}
+
+export function mathjaxPlugin(options: MathJaxOptions = {}) {
+  let adaptor: any
+  let initialized = false
+
+  async function ensureInitialized() {
+    if (!initialized) {
+      await initializeMathJax(options)
+      adaptor = MathJax.startup.adaptor
+      initialized = true
+    }
+  }
+
+  function renderMath(content: string, displayMode: boolean): string {
+    if (!initialized) {
+      throw new Error('MathJax not initialized')
+    }
+
+    const node = MathJax.tex2svg(content, { display: displayMode })
+
+    // Prevent Vue from touching MathJax output
+    adaptor.setAttribute(node, 'v-pre', '')
+
+    let html = adaptor.outerHTML(node)
+
+    // Preserve spaces inside mjx-break (SVG only)
+    html = html.replace(
+      /<mjx-break(.*?)>(.*?)<\/mjx-break>/g,
+      (_: string, attr: string, inner: string) =>
+        `<mjx-break${attr}>${inner.replace(/ /g, '&nbsp;')}</mjx-break>`,
+    )
+
+    // Wrap only display equations (not inline math)
+    html = html.replace(
+      /(<mjx-container[^>]*display="true"[^>]*>)([\s\S]*?)(<\/mjx-container>)/,
+      '<div class="mjx-scroll-wrapper">$1$2$3</div>'
+    )
+
+    return html
+  }
+
+  function getMathJaxStyles(): string {
+    return initialized
+      ? adaptor.textContent(MathJax.svgStylesheet()) || ''
+      : ''
+  }
+
+  function resetMathJax(): void {
+    if (!initialized) return
+    MathJax.texReset()
+    MathJax.typesetClear()
+  }
+
+  function viteMathJax(): VitePlugin {
+    const virtualModuleID = '\0' + mathjaxStyleModuleID
+
+    return {
+      name: 'mathjax-styles',
+
+      resolveId(id) {
+        if (id === mathjaxStyleModuleID) {
+          return virtualModuleID
+        }
+      },
+
+      async load(id) {
+        if (id === virtualModuleID) {
+          await ensureInitialized()
+          return getMathJaxStyles()
+        }
+      },
+    }
+  }
+
+  function mdMathJax(md: MarkdownIt): void {
+    mdTex(md, {
+      render: renderMath,
+    })
+
+    const orig = md.render
+    md.render = function (...args) {
+      resetMathJax()
+      return orig.apply(this, args)
+    }
+  }
+
+  const init = ensureInitialized()
+
+  return {
+    vitePlugin: viteMathJax(),
+    markdownConfig: mdMathJax,
+    styleModuleID: mathjaxStyleModuleID,
+    init,
+  }
+}